1. Field of the Invention
The present invention relates to an imaging device and an automatic focus adjustment method, and particularly to an imaging device and an automatic focus adjustment method for detecting a phase difference between imaged signals and automatically performing a focus adjustment.
2. Description of the Related Art
Conventionally, there is known an automatic focus adjustment (phase difference AF) in which first and second phase-difference pixels are provided in parts of an imaging element, a phase difference between the output signals of the first and second phase-difference pixels is detected, and the focal position of a focus lens is adjusted based on the detected phase difference.
When the first and second phase-difference pixels are provided in parts of the imaging element, there is a problem in that the focus detection accuracy decreases by the influence of a crosstalk from other pixels with different colors that are adjacent to the first and second phase-difference pixels.
For solving this problem, a focus detection device described in Japanese Patent Application Laid-Open No. 2009-122524 corrects the output signals of the first and second phase-difference pixels, depending on the output signals of surrounding pixels, and detects the phase difference based on the signals after the correction.
Meanwhile, the saturation of pixels adjacent to the phase-difference pixels creates another problem in that the crosstalk correction is not properly performed and an error appears in the focus detection result.
For solving this problem, an imaging device described in Japanese Patent Application Laid-Open No. 2011-257565 decides whether pixels surrounding the phase-difference pixels are saturated, and switches the crosstalk correction depending on the decision result.